Analisis Debit Air Limpasan Di Permukaan (Run Off) Pada Das Batang Kandih Dan Das Air Dingin Sebagai Penyebab Terjadinya Genangan Di Kota Padang

Abstract

Abstract.The Purpose of this study is to calculate rainwater discharge into the ground
through the infiltration process and water discharge that become a inundation on the
surface, when it rains highest in on the DAS Batang Kandih and DAS Air Dingin. DAS Air
Dingin has an infiltration rate of around 0,10852 cm/minutes and the value of infiltration in
the DAS Air Dingin is 65.402,5331 m3/hour/km2 with catchment area 20.844 km2 and soil
catchment area on the DAS Air Dingin very low with time around 0,1 to 0,2 per minutes.
Meanwhile infiltration rate on the DAS Batang Kandih is 0,128 cm/minutes and the value of
infiltration in the study area is 76.775,58 m3/hour/km2. Form the result of this study the
infiltration value in this area as very small because it enters the VI/E zone. Calculation of
average daily maximum rainfall using Polygon Thiessen Method is 163,359 mm/day with a
return period of 25 years of rainfall is 277,005 mm/day. Rain intensity at DAS Air Dingin is
32,760 hours and rain intensity at DAS batang Kandih is 32,935 hours. calculation of run
off discharge value at DAS Air Dingin is 811,370 m3/seconds and calculation of run off
discharge value at DAS Batang Kandih is 863,188 m3/seconds.

Keywords:infiltration, rainfall, rainfall return period, rain intensity, run off